Railway car drawbar assemblies and the like are frequently provided with slack adjustment and cushioning to protect the metal parts from the tremendous forces imposed upon them as fully loaded railroad cars accelerate and decelerate. See, for example, Payton U.S. Pat. No. 4,531,648, Altherr, U.S. Pat. No. 4,422,557, and Fishbaugh, U.S. Pat. No. 3,480,268. See also the abandoned U.S. patent application Ser. No. 577,228 of Carl B. McClurg et al, filed Feb. 6, 1984 and entitled Drawbars for Connecting Railcars, which discloses a prior art design of drawbar assembly which was built and tested by the assignee of this present application.
Existing drawbar assemblies slide laterally on the pin and jacknife when the system is in buff (i.e. when the railroad cars are decelerating). This motion causes high forces which wear and/or peen the existing sill structure of the railroad cars in such a manner that the condition worsens with use. This motion can cause the drawbar pin bearing block not to act in a purely radial relationship with the rear butt of the drawbar, thus causing extreme forces and metal flow in the pin bearing block, with resulting undesirable rapid wear.
Additionally, while existing drawbar assemblies have slack adjusting wedges within the sill to compensate for wear during operation, the wear condition of the parts and the amount of remaining possible slack adjustment cannot be determined in prior designs by casual inspection. Some designs of the prior art can be examined through small inspection holes in the sill, while others require examination from under the railroad car. If adjustment of the device is required, the slack adjustment wedges must be raised, the drawbar pin removed, and the railroad cars separated enough to put shims behind the follower blocks or slack adjusting wedge assemblies.
By this invention, the above described deficiencies of prior art devices are addressed with new and improved structure, to avoid the disadvantages of prior art drawbar assemblies, resulting in a structure which exhibits significantly improved wear characteristics, and greater ease of adjustability.